127. What are paramagnetic and ferromagnetic substances. Account for the paramagnetic character of transition metal compounds. How does the paramagnetic character of the bivalent ions of the first transition metal series varies from Ti (Z = 22) to Cu (Z = 29)?

Paramagnetic substances are attracted by the magnetic field. This is due to the presence of unpaired electrons in the atoms/ions/molecules of the paramagnetic substance. Paramagnetism is a temporary effect.

Ferromagnetic substances are strongly attracted by the magnetic field. They show magnetism even when the magnetic field is removed. This is due to a spontaneous alignment of the magnetic dipole in the same direction.

Transition metal compounds contains one or more unpaired electrons. So, these compounds show para magnetism. The paramagnetism of the bivalent ions of the first transition metal series first increases in going from Ti²⁺ to Mn²⁺ (number of unpaired electrons increases) and then decreases upto Cu²⁺ (because the number of unpaired electrons decreases).
Transition metal compounds contains one or more unpaired electrons. So, these compounds show para magnetism. The paramagnetism of the bivalent ions of the first transition metal series first increases in going from Ti²⁺ to Mn²⁺ (number of unpaired electrons increases) and then decreases upto Cu²⁺ (because the number of unpaired electrons decreases).